JP4400888B2 - Laser irradiation apparatus and laser thermal transfer method - Google Patents

Description

  The present invention relates to a laser irradiation apparatus and a laser thermal transfer method.

  In general, an organic electroluminescent element which is a flat panel display element includes an anode electrode, a cathode electrode, and an organic film layer interposed between the anode electrode and the cathode electrode. Such organic electroluminescent devices are classified into high-molecular organic electroluminescent devices and low-molecular organic electroluminescent devices depending on the organic film layer, in particular, the material constituting the light-emitting layer.

  In order to realize full color in such an organic electroluminescent device, the light emitting layer must be patterned. As a method for patterning the light emitting layer, in the case of a low molecular organic electroluminescent device, there is a method using a shadow mask, and in the case of a polymer organic electroluminescent device, ink jet printing (ink-jet printing) is used. Alternatively, a laser thermal transfer method (Laser Induced Thermal Imaging; hereinafter referred to as LITI) may be used. Of these, LITI has the advantages that it can finely pattern the organic film layer, can be used over a large area, and is advantageous for high resolution, but it is also a wet process for inkjet printing. In contrast, LITI has the advantage of being a dry process.

  Such LITI is a transfer method using a laser, and in order to form an organic film layer or the like using this, at least a light source, a substrate and a donor substrate are required. As a light source, a laser beam generated from a laser irradiation device is used. Related prior arts are disclosed in Patent Literature 1, Patent Literature 2, Patent Literature 3 and Patent Literature 4.

  FIG. 1 is a schematic diagram for explaining a laser irradiation apparatus and a laser thermal transfer method according to the prior art.

  Referring to FIG. 1, a donor substrate 150 is laminated on an acceptor substrate 160 provided with predetermined elements. The donor substrate 150 includes a base substrate 151, a light-to-heat conversion layer (LTHC) 152 positioned in contact with the base substrate 151, and a transfer layer 153 positioned in contact with the light-heat conversion layer 152. The

  At this time, a laser beam generated from the laser irradiation apparatus 100 is used as a light source irradiated onto the donor substrate 150.

  The laser irradiation apparatus 100 includes a laser generator 110, a patterned mask 120, and a projection lens 130.

  A laser beam 140 is irradiated onto a predetermined region of the base substrate 151 using the laser generator 110. At this time, the laser beam 140 generated from the laser generator 110 passes through the patterned mask 120, and the passed laser beam 140 is refracted by the projection lens 130 and irradiated onto the base substrate 151. The laser beam 140 is blocked at the unpatterned portion of the mask 120.

  The laser beam 140 applied to a predetermined region of the base substrate 151 is absorbed by the photothermal conversion layer 152 and converted into thermal energy. Gas is generated from the photothermal change layer 152 by the absorbed heat energy, and the photothermal conversion layer 152 is expanded. The swelled photothermal change layer 152 causes the transfer layer 153 to adhere to the acceptor substrate 160. The transferred transfer layer 153 is transferred to the acceptor substrate 160 after the bond in the donor substrate 150 is disconnected.

Korean Patent Application No. 1998-51844 US Pat. No. 5,998,085 US Pat. No. 6,214,520 US Pat. No. 6,114,088

  At this time, if the temperature of the transfer layer 153 rises excessively due to the transferred thermal energy, the transfer layer 153 may be deteriorated. In order to prevent this, if a high-intensity laser beam is used, the transfer layer 153 can be prevented from deteriorating. However, the transfer layer is combined at the stepped portion of the acceptor substrate 160. In other words, a portion that is not transferred is generated. This is called edge open failure (edge open) or non-transfer failure. This is because since the laser beam is irradiated in a short time, the temperature of the photothermal conversion layer 152 is not yet sufficiently increased and is not easily deformed.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to prevent the transfer layer from being deteriorated in the transfer process using LITI, and to provide a step difference of the acceptor substrate. It is an object of the present invention to provide a new and improved laser irradiation apparatus and laser thermal transfer method that can perform transfer well even in the presence of the laser beam.

In order to solve the above-described problem, according to an aspect of the present invention, a predetermined region of a donor substrate is irradiated with a laser beam through a mask patterned corresponding to a transfer pattern, and is positioned in the predetermined region of the donor substrate. A preheating laser generator for selectively deforming the transfer layer ; irradiating a predetermined region of the donor substrate with a laser beam through a mask on which the transfer pattern is patterned, positioned in the predetermined region of the donor substrate, and for preheating And a patterning laser generator for selectively transferring a transfer layer selectively deformed by a laser beam of the laser generator from a donor substrate onto an acceptor substrate. The The preheating laser generator may be disposed in front of the patterning laser generator in the scanning direction of the laser beam.

In order to solve the above problems, according to another aspect of the present invention , a laser beam is applied to a predetermined region of a donor substrate through a mask patterned in accordance with a transfer pattern using a preheating laser generator. And selectively deforming a transfer layer located in a predetermined region of the donor substrate ; and using a patterning laser generator, a laser beam is applied to the predetermined region of the donor substrate through a mask on which the transfer pattern is patterned. And selectively transferring a transfer layer located in a predetermined region of the donor substrate and selectively deformed by the laser beam of the preheating laser generator from the donor substrate onto the acceptor substrate. There is provided a laser thermal transfer method characterized by comprising.

  The laser irradiation device may further include a beam shaping device disposed below the preheating laser generator.

  The patterning laser generator and the preheating laser generator may generate laser beams having different wavelengths.

  Further, the laser beam generated from the patterning laser generator may have a greater intensity than the laser beam generated from the preheating laser generator.

  Further, the patterning laser generator and the preheating laser generator may each generate a laser beam so as to have overlapping portions in the irradiated region.

  The donor substrate may include a base substrate, a photothermal conversion layer (LTHC) located on the base substrate, and a transfer layer located on the photothermal conversion layer.

  Further, the laser beam generated from the preheating laser generator may raise the temperature of the photothermal conversion layer to the glass transition temperature (Tg) of the transfer layer.

  The donor substrate may further include a buffer layer positioned between the photothermal conversion layer and the transfer layer.

  Further, the laser beam generated from the preheating laser generator may raise the temperature of the buffer layer to the glass transition temperature (Tg) or less of the transfer layer.

  Moreover, the pixel electrode which comprises an organic electroluminescent element may be provided on the acceptor substrate.

  The transfer layer may be made of an organic material.

  As described above, according to the laser irradiation apparatus and the laser thermal transfer method of the present invention, it is possible to prevent the transfer layer from deteriorating in the transfer process using LITI, and at the same time, the portion where the step of the acceptor substrate exists. However, transfer can be performed satisfactorily without causing edge open defects.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
First, a laser irradiation apparatus and a laser thermal transfer method according to the first embodiment of the present invention will be described. 2A and 2B are schematic views for explaining the laser irradiation apparatus and the laser thermal transfer method according to the first embodiment of the present invention.

  Referring to FIG. 2A, the donor substrate 150 is laminated on the acceptor substrate 160. The donor substrate 150 preferably has a size that can cover the entire acceptor substrate 160, but a substrate having a size smaller than the acceptor substrate 160 may be used as necessary.

  On the acceptor substrate 160, predetermined elements constituting an organic electroluminescent element are provided. That is, a thin film transistor, a planarizing film located on the thin film transistor, and a pixel electrode located on the planarizing film can be provided.

  The donor substrate 150 is a donor substrate for an organic electroluminescent element. That is, the base substrate 151, a light-to-heat conversion layer (LTHC) 152 positioned in contact with the base substrate 151, and a transfer layer 153 positioned in contact with the light-heat conversion layer 152 can be configured. .

  The base substrate 151 is made of a transparent polymer. As such a polymer, polyester such as polyethylene and terephthalate, polyacryl, polyepoxy, polyethylene, polystyrene and the like can be used.

  The photothermal conversion layer 152 is a light source, that is, a layer that absorbs a laser beam and converts it into heat, and uses one of an organic film, a metal, or a composite layer containing a laser beam absorbing material. Can be configured.

  A gas generation layer (not shown) can be formed at a position adjacent to the photothermal conversion layer 152. The gas generating layer, when absorbing light or heat, causes a decomposition reaction and releases nitrogen gas, hydrogen gas, etc., thereby providing transfer energy, such as pentaerythritol tetranitrate (PETN), trinitrotoluene. (TNT) or the like. Since the gas generation layer must transfer heat from the light-to-heat conversion layer 152, the gas generation layer is disposed adjacent to the upper or lower portion of the light-to-heat conversion layer 152, or mixed with a substance constituting the light-to-heat conversion layer 152, Layers can be constructed.

  The transfer layer 153 is a material film that is patterned on the acceptor substrate 160 and is made of an organic material. When an organic electroluminescent device is manufactured using the donor substrate 150, the donor substrate 150 includes an organic film for a hole injection layer, an organic film for a hole transport layer, an organic film for a light emitting layer, and an organic film for a hole suppression layer. , One single layer film selected from the group consisting of an organic film for an electron transport layer and an organic film for an electron injection layer, or a multilayer film structure of two or more types. Furthermore, the organic film is a high molecular substance or a low molecular substance. On the other hand, the transfer layer 153 is formed using one method selected from the group consisting of extrusion, spin coating, knife coating, vacuum deposition, and CVD (Chemical Vapor Deposition).

  A buffer layer (not shown) can be further formed between the photothermal conversion layer 152 and the transfer layer 153. The buffer layer serves to control the adhesive force with the transfer layer 153 so that the transfer pattern characteristics are improved.

  The donor substrate 150 can further include a layer having various uses as well as the base substrate, the photothermal conversion layer, the transfer layer, the gas generation layer, and the buffer layer, and the laminated structure is changed according to the use. Can be used.

  A predetermined region of the donor substrate 150 laminated on the acceptor substrate 160 is irradiated with a laser beam, and the transfer layer 153 is transferred onto the acceptor substrate 160.

  At this time, a laser beam generated from the laser irradiation apparatus 200 is used as a light source irradiated onto the donor substrate 150.

  The laser irradiation apparatus 200 includes a laser generator 210. In the present embodiment, a laser generator 210 including a patterning laser generator 211 and a preheating laser generator 212 is employed.

  The patterning laser generator 211 separates the transfer layer 153 from the donor substrate 150, transfers it onto the acceptor substrate 160, and generates a laser beam 240 necessary to form a predetermined pattern. Therefore, the intensity of the laser beam 240 generated from the patterning laser generator 211 has such an intensity that the bond in the transfer layer 153 can be broken.

  The preheating laser generator 212 generates a laser beam 245 that preheats the donor substrate 150. That is, the photothermal conversion layer 152 and the buffer layer are preheated to a certain temperature to facilitate deformation.

  The laser beam 245 generated from the preheating laser generator 212 is absorbed by the photothermal conversion layer 152 and converted into heat. At this time, since the temperature of the light-to-heat conversion layer 152 is increased by the generated heat, the laser beam 245 is irradiated so as to increase to the glass transition temperature (Tg) of the transfer layer 153. Glass transition temperature refers to the temperature at which a material softens, and glass transition is a phenomenon that occurs in polymer materials. That is, the polymer substance acts like a rubber at a temperature higher than the glass transition temperature, and acts as hard and fragile like glass at a temperature lower than the glass transition temperature.

  Therefore, heat is transferred from the photothermal conversion layer 152 whose temperature has risen to the glass transition temperature of the transfer layer 153 to the transfer layer 153, and the transfer layer 153 is maintained in a state where it can be easily deformed. However, it is not always necessary to raise the temperature of the photothermal conversion layer 152 to the glass transition temperature of the transfer layer 153. If the transfer layer 153 is easily deformed, the temperature is raised to a temperature lower than the glass transition temperature of the transfer layer 153. It doesn't matter.

  When a buffer layer is formed between the photothermal conversion layer 152 and the transfer layer 153, the temperature of the buffer layer is raised to the glass transition temperature of the transfer layer 153.

  Therefore, even if the high-intensity laser beam 240 generated from the patterning laser generator 211 is irradiated, the donor substrate 150 is easily deformed by the laser beam 245 generated from the preheating laser generator 212. Even at the portion where the step is formed, the transfer can be performed satisfactorily.

  A patterned mask 220 is disposed below the patterning laser generator 211, and a projection lens 230 is disposed below the mask 220.

  The laser beam 240 generated from the patterning laser generator 211 passes through the mask 220 being patterned, and the laser beam 240 that has passed through is refracted by the projection lens 230 and irradiated onto the base substrate 151. The laser beam 240 is blocked at the unpatterned portion of the mask 220.

  A beam shaping device 235 is disposed below the preheating laser generator 212. The beam shaping device 235 may be provided with a fly eye lens, a cylindrical lens, or the like. Therefore, the laser beam 240 generated from the patterning laser generator 211 has a uniform intensity via the beam shaping device 235, and is shaped into a certain shape, for example, a square shape or a circular shape.

  The patterning laser generator 211 and the preheating laser generator 212 respectively irradiate the base substrate 151 of the donor substrate 150 with laser beams 240 and 245.

  The preheating laser generator is disposed in front of the patterning laser generator in the scanning direction of the laser beams 240 and 245. As a result, the laser beam 245 generated from the preheating laser generator preheats the donor substrate 150 and facilitates the laser beam 240 generated from the patterning laser generator to raise the temperature of the transfer layer 153.

  Each of the generated laser beams 240 and 245 preferably has a different wavelength. In particular, the intensity of the laser beam 240 generated from the patterning laser generator 211 is greater than the intensity of the laser beam 245 generated from the preheating laser generator 212. Since the laser beam 240 generated from the patterning laser generator 211 is used to break the bond in the transfer layer 153, the intensity is higher than the laser beam 245 used to preheat the donor substrate 150.

  FIG. 2B is a diagram showing a laser beam irradiated on the donor substrate.

  Referring to FIG. 2B, the laser beam 240 generated from the patterning laser generator 211 is a multi-beam having a certain pattern by the patterned mask 220 and is irradiated onto the base substrate 151.

  On the other hand, the laser beam 245 generated from the preheating laser generator 212 is shaped and irradiated by the beam shaping device 235 into a single laser beam 245 having a square shape.

  At this time, the laser beams 240 and 245 have regions 246 that overlap each other. Since the laser irradiation apparatus 200 advances the transfer process while scanning in the direction of the arrow, the transfer layer 150 can be transferred onto the acceptor substrate 160 at the same time as the donor substrate 150 is preheated.

  In the case where the laser beams 240 and 245 do not have a region where they overlap each other, the temperature of the donor substrate 150 may be decreased because the donor substrate 150 is patterned after a predetermined time after preheating.

  As a result, a layer having a desired pattern can be transferred onto the acceptor substrate 160. In particular, when a pixel electrode constituting an organic electroluminescent element is provided on the acceptor substrate 160, an organic light emitting layer or the like can be transferred onto the acceptor substrate 160.

(Second Embodiment)
Next, a laser irradiation apparatus and a laser thermal transfer method according to the second embodiment of the present invention will be described. 3A and 3B are schematic views for explaining a laser irradiation apparatus and a laser thermal transfer method according to a second embodiment of the present invention.

  Referring to FIG. 3A, the donor substrate 150 is laminated on the acceptor substrate 160. The laser irradiation apparatus 300 includes a laser generator 310.

  A patterned mask 320 is disposed below the patterning laser generator 311, and a projection lens 330 is disposed below the mask 320.

  A patterned mask 325 is disposed below the preheating laser generator 312, and a projection lens 335 is disposed below the mask 325.

  The laser beams 340 and 345 generated from the patterning laser generator 311 and the preheating laser generator 312 pass through the masks 320 and 325 that are patterned, and the laser beams 340 and 345 that have passed through are projected by the projection lenses 330 and 335. The light is refracted and irradiated onto the base substrate 151. The laser beams 340 and 345 are blocked at the unpatterned portions of the masks 320 and 325.

  In the present embodiment, a patterned mask 325 and a projection lens 335 are disposed below the preheating laser generator 312. Therefore, the laser beam 345 is irradiated with multiple beams.

  Referring to FIG. 3B, it can be seen that the laser beam 340 generated from the patterning laser generator 311 and the laser beam 345 generated from the preheating laser generator 312 are irradiated with multiple beams.

  At this time, the laser beams 340 and 345 have regions 346 that overlap each other.

  This embodiment is the same as the laser irradiation apparatus and laser thermal transfer method according to the first embodiment of the present invention except for the above matters.

  As described above, according to the embodiment of the present invention, the laser irradiation apparatus including the patterning laser generator and the preheating laser generator is used in the transfer process using LITI. By using a high-intensity laser beam generated from the patterning laser generator, it is possible to prevent the transfer layer from deteriorating, and at the same time, by preheating with the laser beam generated from the preheating laser generator, There is an advantage that transfer can be performed satisfactorily without occurrence of an edge open defect even in a portion where the step of the acceptor substrate exists.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

It is a schematic diagram explaining the laser irradiation apparatus and laser thermal transfer method which concern on a prior art. It is a schematic diagram explaining the laser irradiation apparatus and laser thermal transfer method which concern on 1st Embodiment of this invention. It is a schematic diagram explaining the laser irradiation apparatus and laser thermal transfer method which concern on 1st Embodiment of this invention. It is a schematic diagram explaining the laser irradiation apparatus and laser thermal transfer method which concern on 2nd Embodiment of this invention. It is a schematic diagram explaining the laser irradiation apparatus and laser thermal transfer method which concern on 2nd Embodiment of this invention.

Explanation of symbols

150 donor substrate 151 base substrate 152 photothermal conversion layer 153 transfer layer 160 acceptor substrate 200,300 laser irradiation device 210,310 laser generator 211,311 patterning laser generator 212,312 preheating laser generator 220,320,325 mask 230, 330, 335 Projection lens 235 Beam shaping device 240, 245, 340, 345 Laser beam 246, 346 Area where laser beam generated from patterning laser generator and laser beam generated from preheating laser generator overlap each other

Claims (16)

A preheating laser generator that irradiates a predetermined region of the donor substrate with a laser beam through a mask patterned corresponding to the transfer pattern and selectively deforms a transfer layer located in the predetermined region of the donor substrate ;
A predetermined region of the donor substrate is irradiated with a laser beam through a mask on which the transfer pattern has been patterned, is positioned in the predetermined region of the donor substrate, and is selectively deformed by the laser beam of the preheating laser generator A patterning laser generator for selectively transferring the transferred layer from the donor substrate onto the acceptor substrate ;
A laser irradiation apparatus comprising:   The laser irradiation apparatus according to claim 1, further comprising a beam shaping device disposed below the preheating laser generator.   The laser irradiation apparatus according to claim 1, wherein the patterning laser generator and the preheating laser generator generate laser beams having different wavelengths.   4. The laser irradiation apparatus according to claim 1, wherein the laser beam generated from the patterning laser generator has a greater intensity than the laser beam generated from the preheating laser generator. .   5. The laser irradiation according to claim 1, wherein laser beams respectively generated from the patterning laser generator and the preheating laser generator have overlapping portions in an irradiated region. apparatus. Using a preheating laser generator, a predetermined region of the donor substrate is irradiated with a laser beam through a mask patterned corresponding to the transfer pattern, and the transfer layer located in the predetermined region of the donor substrate is selectively deformed. And a stage of
Using a patterning laser generator, a predetermined region of the donor substrate is irradiated with a laser beam through a mask on which the transfer pattern is patterned, and the preheating laser is generated in a predetermined region of the donor substrate. Selectively transferring the transfer layer selectively deformed by a laser beam of the vessel from the donor substrate onto an acceptor substrate ;
A laser thermal transfer method characterized by comprising:   The laser thermal transfer method according to claim 6, wherein the laser irradiation device further includes a beam shaping device disposed below the preheating laser generator.   8. The laser thermal transfer method according to claim 6, wherein the patterning laser generator and the preheating laser generator generate laser beams having different wavelengths.   9. The laser thermal transfer method according to claim 6, wherein the laser beam generated from the patterning laser generator has a greater intensity than the laser beam generated from the preheating laser generator. .   The laser beam generator for patterning and the laser generator for preheating respectively generate the laser beams so as to have overlapping portions in the irradiated region. The laser thermal transfer method described. The donor substrate includes a base substrate, a light-to-heat conversion layer (LTHC) located on the base substrate, characterized by comprising said transfer layer positioned on the light-to-heat conversion layer, according to claim 6-10 The laser thermal transfer method described in 1.   The laser thermal transfer method according to claim 11, wherein the laser beam generated from the preheating laser generator raises the temperature of the photothermal conversion layer to the glass transition temperature (Tg) of the transfer layer.   The laser thermal transfer method according to claim 11, wherein the donor substrate further includes a buffer layer positioned between the photothermal conversion layer and the transfer layer.   The laser thermal transfer method according to claim 13, wherein the laser beam generated from the preheating laser generator raises the temperature of the buffer layer to the glass transition temperature (Tg) of the transfer layer.   The laser thermal transfer method according to claim 11, wherein a pixel electrode constituting an organic electroluminescent element is provided on the acceptor substrate. The laser thermal transfer method according to claim 15, wherein the transfer layer is made of an organic material.

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